There are several situations in medicine where it is necessary to pump blood, by means of an artificial device.
1. During open heart surgery by means of what is called the extracorporeal circulation (ECC).
2. In acute cardiac or respiratory failure in which the so-called extracorporeal membrane oxygenator is used (ECMO).
3. In patients with profound ventricular failure in which the so-called artificial ventricles may be used.
4. In Hemodialysis with the so-called artificial kidney and in the new apheresis systems.
All these cases need to use a device which pumps blood, with the following features:
1. Be effective from a hemodynamic point of view, i.e. they must be capable of supplying an appropriate blood flow in all the conditions which may arise within the specific application.
2. The mechanical effort which the blood forming elements are submitted to, especially red globules, must be minimal, i.e. homolysis must not arise.
3. They must not produce any formation of added plaques nor thrombi which may be released and lead to embolies in the patient.
Optimization of the blood pumps depends on four types of solutions.
A. Solutions which help to reduce the formation of platelet aggregates and thrombi, basically aimed at being designed so as to avoid areas of blood stagnation.
B. Solutions aimed at reducing the lesions produced in the blood forming elements.
C. Solutions aimed at reducing the cost of the device in order to extend its application field.
D. In some applications such as the use of artificial ventricules there must be solutions to improve the filling up of the blood chamber.